Regular Expressions 101

Pro

^start of line

Group 1([+-]?[1-9][0-9]*|0)

1st Alternative[+-]?[1-9][0-9]*

Character Class[+-]?

?matches at most one character from the set below:

+the literal + (43₁₀ / 53₈ / 2B₁₆)

-the literal - (45₁₀ / 55₈ / 2D₁₆)

Character Class[1-9]

1-9one character from 1 (49₁₀) to 9 (57₁₀)

Character Class[0-9]*

*matches any number of characters from the set below:

0-9one character from 0 (48₁₀) to 9 (57₁₀)

2nd Alternative0

0the literal 0 (48₁₀ / 60₈ / 30₁₆)

$end of line

Global pattern flags

g modifier: global. Finds all matches instead of stopping after the first

m modifier: multiline. Causes ^ and $ to match the start and end of each line, not only the start and end of the string

Detailed match information will be displayed here automatically.

25 tokens

Regular Expression

^([+-]?[1-9][0-9]*|0)$

Here are some test cases

0
1
-1
+1
A1
)1
0.1
0001
1,000
1.1
This is what the result must be

1 #true
-1 #true
+1 #true
A1 #false
)1 #false
0.1 #false
0001 #false
1,000 #false
1.1 #false

Extraction

Here are some test cases

0
1
-1
+1
A1
)1
0.1
0001
1,000
1.1
This is what the result must be

1 #true
-1 #true
+1 #true
A1 #false
)1 #false
0.1 #false
0001 #false
1,000 #false
1.1 #false